Time travel, especially literary time travel, is the kind of thing that can make your head hurt if you start thinking about it too much. If the time travel in A WRINKLE IN TIME or HARRY POTTER AND THE PRISONER OF AZKABAN has you scratching or shaking your head in puzzlement, Rebecca Stead’s new novel just might help you figure things out.

Stead gained a reputation for incorporating scientific ideas into entertaining narratives with her debut novel, rebecca LIGHT, about a previously undiscovered society living below the ice in Greenland. She continues exploring mathematical and scientific concepts in her newest work, doing so in clever and often surprising ways.

Miranda knows that she and her mom aren’t rich, but they manage to get by in their rundown apartment in their slightly sketchy New York City neighborhood. Miranda’s mom, a paralegal who’s balking at the thought of moving in with her boyfriend, dreams of fame and fortune on the popular “$20,000 Pyramid” television show (the year, by the way, is 1979). As for Miranda, she’s more worried about just making it through the day without getting harassed by the bullies who haunt the sidewalks between school and home or being accosted by the elderly homeless “laughing man” who lives on their corner. He chants weird sayings, and he sometimes seems oddly insightful --- or sometimes just plain crazy.

Lately, Miranda has had to navigate this tricky territory --- not to mention the pitfall-laden halls of school itself --- on her own, since her best friend Sal has suddenly decided to act like she doesn’t even exist. Why is Sal so distant? Why does the big boy who beat Sal up actually seem gentle, even wise? Can Miranda find happiness with other friends, even if they come from fancier apartment buildings and have more money than she does?

Questions abound, but the biggest mystery of all is who is sending Miranda scarily prophetic notes. These letters mention specific times and places of things that haven’t yet happened when Miranda receives them but that, eerily, come to pass exactly as the anonymous writer says they will. Could the answer be hidden in the pages of Miranda’s favorite book, which she reads over and over again: A WRINKLE IN TIME by Madeleine L’Engle?

With its explanations and explorations of time travel, WHEN YOU REACH ME does share a great deal with L’Engle’s novel. With its focus on a girl learning to independently navigate her Manhattan neighborhood, it also will remind some readers of other classics like HARRIET THE SPY and FROM THE MIXED-UP FILES OF MRS. BASIL E. FRANKWEILER. And, just as Miranda does with her own favorite novel, the mind-bending conclusion of this one will prompt many readers to flip back to page one and read it all over again, picking up on clues they missed (or didn’t understand) the first time around.

With a well-paced plot, engaging characters, strong family portrayals, and a compelling mystery to solve, WHEN YOU REACH ME is a great novel for adults and kids to read together, sharing ideas on what might be happening in Miranda’s world and jointly exploring their own theories to explain it all.